You will have to go through the below steps -

1. First of all, you will have to earn a bachelors degree which can be in any major.

2. Get flying experience as aspiring airline pilots are required to complete a certain number of hours of flight training to qualify for licensure.

3.Get a pilot's licence as obtain a pilot’s license, a minimum number of hours of flight experience must be completed.

4.Complete additional test and training as many airline companies require pilots to take physical, psychological and aptitude tests, as well as drug tests as a prerequisite for employment. Also, if you have completed your 12th then you will have to go through NDA exam. UPSC conducts the NDA (National Defence Academy) exam, clearing which you undergo a 3-year training at NDA, Khadakwasla, followed by flying training at Air Force Training establishments. Post this, you will be commissioned as “permanent commission officers” and may be posted as pilots at any Air Force station.

Hope this helps!!!